Additive antitumor effect of arsenic trioxide with exposure to ionizing radiation to human acute promyelocytic leukemia HL­60 cells.

Arsenic trioxide (ATO) is expected to be a chemical drug with antitumor activity against acute promyelocytic leukemia (APL), a type of acute myeloid leukemia. In Japan, its antitumor effects were confirmed in clinical trials for APL, and it has been approved in various countries around the world. However, there have been no reports on ATO's antitumor effects on radioresistant leukemia cells, which can be developed during radiotherapy and in combination with therapeutic radiation beams. The present study sought to clarify the antitumor effect of ATO on APL cells with radiation resistance and determine its efficacy when combined with ionizing radiation (IR). The radiation­resistant HL60 (Res­HL60) cell line was generated by subjecting the native cells to 4­Gy irradiation every week for 4 weeks. The half­maximal inhibitory concentration (IC50) for cell proliferation by ATO on native cell was 0.87 µM (R2=0.67), while the IC50 for cell proliferation by ATO on Res­HL60 was 2.24 µM (R2=0.91). IR exposure increased the sub­G1 and G2/M phase ratios in both cell lines. The addition of ATO resulted in a higher population of G2/M after 24 h rather than 48 h. When the rate of change in the sub­G1 phase was examined in greater detail, the sub­G1 phase in both control cells without ATO significantly increased by exposure to IR at 24 h, but only under the condition of 2 Gy irradiation, it had continued to increase at 48 h. Res­HL60 supplemented with ATO showed a higher rate of sub­G1 change at 24 h; however, 2 Gy irradiation resulted in a decrease compared with the control. There was a significant increase in the ratio of the G2/M phase in cells after incubation with ATO for 24 h, and exposure to 2 Gy irradiation caused an even greater increase. To determine whether the inhibition of cell proliferation and cell cycle disruptions is related to reactive oxygen species (ROS) activity, intracellular ROS levels were measured with a flow cytometric assay. Although the ROS levels of Res­HL60 were higher than those of native cells in the absence of irradiation, they did not change after 0.5 or 2 Gy irradiation. Furthermore, adding ATO to Res­HL60 reduced intracellular ROS levels. These findings provide important information that radioresistant leukemia cells respond differently to the antitumor effect of ATO and the combined effect of IR.

Pump Exchange from a Left Ventricular Assist Device to a Jarvik 2000 with a Postauricular Cable Due to Abdominal Driveline Infection.

Driveline infection in patients with implantable left ventricular assist devices (LVAD) remains common and crucial. Once a driveline exit-site infection reaches the LVAD component, radical treatment such as LVAD exchange may become necessary, although the clinical results are unsatisfactory. The Jarvik 2000 device, which utilizes a postauricular cable, allows the driveline to exit the body behind the ear (postauricular) instead of through an abdominal site. Here, we report the case of a patient who had awaited heart transplantation for more than 6 years and had a critical driveline infection that almost reached the LVAD pump. The patient underwent a pump exchange using the Jarvik 2000 with a postauricular cable, with excellent results. It is a useful replacement option for patients with abdominal driveline infections, owing to its small pump pocket and the availability of an alternative pathway for the driveline.

Robot-Assisted Aortic Valve Replacement　- First Clinical Report in Japan.

BACKGROUND: Robot-assisted valve surgery represents the latest development in the field of minimally invasive approaches. Robotic assistance may provide greater visualization, enhanced dexterity, and greater precision than traditional mini-thoracotomy aortic valve replacement.Methods and Results: Aortic valve replacement operations using the da Vinci Xi Surgical System (Intuitive Surgical Inc., Sunnyvale, CA, USA) were performed on 2 patients, 1 with severe aortic insufficiency and the other with aortic stenosis. Both patients had an uneventful postoperative course and were discharged without any adverse events. CONCLUSIONS: Robot-assisted assisted aortic valve replacement appears feasible and safe in limited cases.